Key-guard for locks



NITED STATES PATENT OFFICE.

J. M. RIX, BOSTON, MASSACHUSETTS.

KEY-GUARD FOR LOCKS.

Specification forming part of Letters Patent No. 51,621, dated December19, 1865.

To all whom it may concern:

Be it known that I, J. M. RIX, of Boston, in

' the county of Suffolk and State of Massachutaken in the line 00 m,Fig. 3; Fig. 3, an endview of the same.

Similar letters of reference indicate correspondin g. parts.

This invention relates to a new and improved device to prevent locksbeing illegitimately opened by operating from the outside of the doorupon a key inserted in the look at the inner side of the door--a meansfrequently resorted to by burglars and thieves to effect an entranceinto a house or into an apartment thereof.

A represents a bar having at one end of it a face-plate, B, at rightangles with an elongation or bar, 0, projecting from it in alineparallel with A. The upper edge of the bar A is notched or toothed toform a rack, a, and the face-plate B has a slot, 12, made in it. (SeeFigs. 1 and 2.)

D represents a case of rectangular form, which is fitted on the bar Aand allowed to slide freely thereon. This case has its sides projectingabove the sides of the bar A, and it is open at its top to receive asupport, 0. This case D is wide enough to receive a slide, E, at oneside of bar A, and at one side of the case there is a pin, (1, whichpasses into a slot, e, in the slide E and serves asa guide for the same,and admits of the slide E moving a certain distance back and forth.

The outer end of the slide E is provided with a head, f, which, when theslide E is fully shoved into the case D, comes in contact with the endof the case. p

In the upper part of the case D, above the bar A, there is placed apawl, F, which is held down into the rack a by means of a spring, g,which, besides performing this function, serves as a support for thesides of the case.

At each side of the caseD there is attached, by a pivot, h, a metalstrip, G, of T shape. The upper prongs of these strips are of hookshape, as shown at i, the pivot h serving as a center for the strips Gto turn upon, and admitting of the prongs 21 being raised and lowered atwill. These strips G are connected at the under side of the case D by anarrow strip, j, which, when the strips G are fully raised,

comes in contact with the bottom of D.

The inner end of the slide E .is beveled at its upper edge, and whensaid slide is fully shoved into the case D it throws the pawl F up freefrom the rack a, to admit of the barA being moved'in the case D; andasmall pin, k, projects down from the bar A to prevent the case Dslipping off from it.

The device is used or applied as follows: Suppose the slide E to be intothe case D and the latter pressed forward against the face-plate B, thisbeing the most compact manner in which to carry the device, place thethumb of the right hand upon the hooks i of the strips G, with theforefinger on the under side of the case D, and press the hooks downeven with the top of D. The key of the lock is then turned so as tothrow its bolt into the socket, or, in other words, the lock is locked,and the bowa of the key will bein a horizontal position, or nearly so.The face-plate B is now hooked upon the shank of the key and the bar orprojection O shoved into the keyhole until the-face plate B comes incontact with the door or lock-case. The hooks c i are then raised andthe case D drawn back until the hooks "L i slip over the inner side ofthe bow a of the key. The slide E is then drawn back, and the pawl Ffalls into the rack a of the bar A, and the key is firmly secured in thelock with its bit b in a horizontal position. The keytherefore cannot bepunched or forced out from the lock or turned when in the look by anyimplement; neither can any one look into the apartment through thekeyhole, as the latter is closed, and the key is prevented from beingturned in consequence of the hooks M catching over the bow of the key.

In order to release the key, the slide E is shoved into the case D andthe pawl F there by raised from the rack a, so that the case D may beshoved forward and thehooks ii moved off from the bow to".

The device may be carried in the pocket without any inconvenience, as itmay be constructed in a very compact manner.

Having thus described my invention, I claim as new and desire to secureby Letters Patent The rack-bar A, provided with the face-plate B andprojecting bar (Lin connection with the case D, provided with the pawl Fand strips G G, with hooks i '5 and the slide E, all arranged to operatein the manner substantially as and for the purpose set forth.

J. M. RIX.

Witnesses J. E. POOR, WM. L. HoDsDoN.

